Abstract: An electrophotographic printing machine of the type having a photoconductive member wherein at least one electrostatic latent image is recorded thereon. A developer roller transports a developer material closely adjacent to the photoconductive member. A controller, coupled to the developer roller, generates a control signal as a function of the measured electrical potential on the photoconductive member. A second developer roller, spaced from the first developer roller, is electrically biased to a fixed potential to deposit developer material on the latent image. A third developer roller, spaced from the second developer roller, also develops the latent image with developer material. The second developer roller is interposed between the first developer roller and the third developer roller. The electrical bias on the third developer roller is controlled by the control signal from the controller.

Abstract: A drive system in which a driven member is mounted on a shaft member to rotate in unison therewith. The driven member has a protrusion extending outwardly from one surface thereof. A retaining ring having an open end is mounted on the shaft member. The open end of the retaining ring meshes with the protrusion extending outwardly from the driven member so as to rotate in unison therewith.

Abstract: A valve which connects selectably one of a plurality of chambers storing different color developer material therein with a developer housing chamber. The valve has one aperture in communication with one of the chambers and another aperture in communication with the other chamber. A shaft is mounted rotatably in the tube. The shaft has a portion thereon adapted to close one of the apertures in the tube with the other aperture remaining open so as to connect selectably either one of the chambers storing the developer material with the chamber of the developer housing. A seal is interposed between the shaft and the tube for sealing the region therebetween. The seal prevents the escape of developer material from the chamber not connected to the developer housing chamber into the developer housing chamber.

Abstract: An apparatus in which successive flexible sheets are advanced from a stack. One edge of the stack of sheets is supported rollably in a substantially vertical orientation. Successive outermost sheets are fed from one side of the stack. The stack of sheets moves toward a sheet feeder so as to position successive outermost sheets of one side thereof in a feeding relationship therewith.

Abstract: A sheet transport in which sheets move along a selected path. A piezoelectric strip is positioned to have the generally planar surface thereof extending in a direction substantially normal to the path of movement of the sheet. As the sheet deflects the piezoelectric strip, an electrical signal is generated indicating the presence of the sheet at that point in the sheet path.

Abstract: An apparatus in which an image on a sheet of support material is fused thereto. A fuser roller is arranged to contact the sheet of support material having the image to be fused thereon. The fuser roller has a heating element disposed internally and extending substantially along the longitudinal axis thereof. The heating element is asymmetrical with respect to a reference axis extending through the center of the fuser roller and normal to the longitudinal axis thereof.

Abstract: An apparatus in which a plurality of sheets are attached to one another to form a booklet thereof. The sheets are compiled to form a set which is then advanced to a stapling apparatus and/or a binding apparatus. The set of sheets may be secured to one another by either stapling, binding, or a combination of both.

Abstract: An electrophotographic printing machine in which a variable magnification optical system is controlled so that information being reproduced from an original document fits on a copy sheet. The size of the original document is sensed. The device sensing the size of the original document has a minimum number of detectors to measure a maximum number of different size original documents. The size of the copy sheet is compared to the size of the original document and an error signal generated indicative of the difference therebetween. This error signal controls the magnification of the optical system.

Abstract: An apparatus in which a latent image recorded on a photoconductive surface is developed. The apparatus has a housing which forms, with the photoconductive surface, a substantially closed volume with the sealing edges of the housing being closely spaced from the photoconductive surface. A magnetic strip is mounted on at least one of the sealing edges of the housing. The magnetic sealing strip prevents the escape of carrier granules from the housing without the carrier granules adhering thereto.

Abstract: An apparatus in which a hinge is formed in successive sheets to permit the sheets to lay substantially flat after being opened when bound to one another in a booklet. The stiffness of successive advancing sheets in a marginal region along a line substantially parallel to an edge of the sheet is reduced to facilitate bending of the sheet. The line of reduced stiffness for successive sheets is offset from one another so as to enable bending of the sheets therealong permitting the open sheets of a booklet of sheets to lay substantially flat.

Abstract: An electrophotographic printing machine in which a latent image is recorded on a photoconductive surface. The latent image is developed with charged, insulating marking particles and magnetic, polar or polarizable marking particles. The charged, insulating marking particles optimize development of low density lines in the latent image with the magnetic, polar or polarizable marking particles optimizing development of halftones in the latent image.

Abstract: An apparatus which seals a housing to prevent the escape of toner particles therefrom. The toner particles are captured and softened to become tacky. Additional toner particles stick to the tacky toner particles preventing their escape. Each successive layer of captured toner particles soften and become tacky capturing other toner particles thereto.

Abstract: An apparatus in which flowing developer material is mixed. A plurality of spaced vanes project outwardly from a dividing plate to define a plurality of sets of chambers arranged in substantially parallel rows. Each chamber is arranged to receive developer material at an entrance aperture and to release the developer material from an exit aperture with the exit aperture being displaced from a position vertically below its entrance aperture. Each row has an alternate series of chambers with their exit apertures spaced respectively to the left and right of the position vertically below their entrance apertures. The entrance apertures and exit apertures of the chambers of different rows are aligned so that on successive recirculations of the developer material, the developer material moves simultaneously from left to right and from row to row, and from right to left and from row to row.

Abstract: An apparatus in which an image region recorded on a photoconductive surface is developed with a developer material comprising at least carrier granules and toner particles. The developer material has the resistivity thereof varying continuously as a function of the electrical field applied thereto. A transport moves the developer material closely adjacent to the photoconductive surface. An alternating electrical field is generated between the transport and the photoconductive surface. The alternating electrical field has an amplitude sufficient to change the resistivity of the developer material to a more conductive state.

Abstract: An apparatus which develops a latent image recorded on a flexble photoconductive member. Developer material comprising conductive carrier granules and magnetic toner particles is transported into contact with the photoconductive member in two development zones. In the first development zone, the flexible photoconductive belt is deflected to wrap about the developer roller. This optimizes development of the solid areas in the latent image. In the second development zone, the developer roller transports the developer material into contact with the latent image. This development zone optimizes development of lines in the latent image with carrier granules adhering to the photoconductive member being removed therefrom.

Abstract: An electrophotographic printing machine in which a magnetic toner image is transferred to a copy sheet from a photoconductive member and fused thereto. The toner image fused to the copy sheet is magnetized and the intensity of the magnetic field generated by the toner image detected to provide a continuous indication of the quality of the toner image fused to the copy sheet.

Abstract: An apparatus in which lateral movement of a moving belt is controlled so that the belt moves in a pre-determined path. The apparatus includes at least one rotatably mounted roller having an elastic membrane entrained thereabout. The coefficient of friction between the elastic membrane and the roller is low so as to form a low friction interface therebetween. A pair of opposed, spaced flanges constrain the belt. As the belt moves in a lateral direction, one of the flanges engages a side edge of the belt to prevent lateral movement thereof. When the side edge of the belt engages the flange, the elastic membrane slips on the roller when the force applied on the side edge of the belt is greater than the maximum frictional force between the roller and the elastic membrane, in the direction of lateral movement of the belt.

Abstract: An apparatus in which a latent image recorded on an image receiving member is developed. A developer roller transports the marking particles into the development zone. The developer roller has the exterior surface thereof roughened forming a multiplicity of peaks extending outwardly therefrom with a coating of polymeric material filling the space between adjacent peaks. A blade is positioned to have the free end thereof contacting the peaks on the developer roller. The blade has a plurality of apertures therein through which the marking particles pass. In this way, the thickness of the layer of marking particles on the developer roller is controlled.

Abstract: An apparatus in which an auger, coupled to a hopper storing toner particles, dispenses toner particles substantially uniformly into a developer mixture. The auger comprises a tubular member having a plurality of apertures therein for discharging toner particles therefrom. A toner transport is disposed interiorly of the tubular member for advancing the toner particles therealong. The toner transport has a helical tooth for advancing the toner particles along the tubular member. The helical tooth has sections thereof deleted therefrom in the region of the apertures in the tubular member to facilitate discharging of the toner particles from the toner member and to prevent caking and clogging thereof.

Abstract: An apparatus in which a latent image recorded on an image receiving member is developed with marking particles. A developer roller transports the marking particles into the development zone. A blade having at least one aperture therein through which the marking particles pass has the free end portion thereof in contact with the developer roller. In this way, the thickness of the layer of marking particles on the developer roller is controlled.